Ovarian malignant mixed mesodermal tumor: the occurrence of hyaline droplets containing alpha 1-antitrypsin

Twenty-one of 22 cases of malignant mixed mesodermal tumor (including carcinosarcoma) of the ovary were found to contain periodic acid-Schiff(PAS)-positive, diastase-resistant hyaline droplets ranging in diameter from less than 1 micrometer to approximately 50 micrometers. Droplets were located both inside and outside undifferentiated mesenchymal cells, predominantly within myxomatous areas. In 13 cases, droplets also occurred in epithelial structures, including areas mimicking ovarian carcinoma. Immunoperoxidase staining for alpha-fetoprotein was consistently negative, but droplets and cell cytoplasm reacted strongly with anti-alpha 1-antitrypsin. Analysis of the structure of droplet antitrypsin may be necessary to determine the origin of the droplets themselves and the possible usefulness of serum alpha 1- antitrypsin as a tumor marker in ovarian carcinoma and malignant mixed mesodermal tumor.